How do I qualify for an Apple rebate?
Purchase the qualifying products from an eligible retailer during the promotion period that is noted on the Terms and Conditions of the rebate. If multiple qualifying products are purchased, all items must be purchased together, at the same time, and on the same receipt. Please note: Apple Online Store purchases must have the the same order number even if your items ship out separately.
From:
http://www.apple.com/promo/faq.html#qualification
For the people that bought already and are planning to claim in 14 days, did they specify that you would need to bring it back in and ring up the transaction again or something?
This is also under the "Online and Phone Purchases" area:
If my Mac order ships prior to the promotion start date, but I receive it within the promotional period, will I qualify for the rebate?
If your computer was sold, shipped, and invoiced to you prior to the promotional period, it does not qualify for a rebate.